The international community of researchers who are members of the American Society for Rickettsiology (ASR) is represented in countries from Australia to Zimbabwe, including, of course, the USA and Europe. This wide geographic representation is fed by the global emergence of vector-borne rickettsial pathogens. The annual meetings of the ASR foster scientific exchange of discoveries and resources even before publication. This has resulted in an interwoven fabric of cooperating members that is highly conducive to the advancement of the field itself and facilitates connections between young investigators with established scientists. At every meeting, the organizers sponsor a junior member (primarily students, postdoctoral researchers and assistant professors) from each attending laboratory, specifically with the aim to strengthen the flow of new information, and to encourage young rickettsiologists to remain in the field. At the end of last year's meeting the organizers invited a discussion among all attendees to identify research areas viewed to be of highest priority for driving advances in rickettsiology. As a result, we propose to organize a 1 and 1/2-day workshop within the framework of the annual ASR meeting that addresses the central theme of Regulation of Gene Expression in Rickettsiae. This will broadly include molecular determinants of successful colonization of the arthropod vector (Abdu Azad UMD, Kevin Macaluso LSU) and the mammalian host (Jere McBride UTMB, Matt Welch UCB, Yasuko Rikihisa OSU), defensive responses of arthropods (Joao Pedra UCR, Viveka Vadyvaloo WSU) and mammals (Guy Palmer WSU, Nahed Ismail UPMC), and genetic manipulation of pathogens to identify the regulatory mechanisms that coordinate this interplay (Ulrike Munderloh UMN, Dan Rockey OR, Daniel Voth AR). The workshop will comprise oral presentations by the key speakers, and additional speakers who will be selected by each key speaker from junior faculty, postdoctoral scientists and students who have submitted abstracts. An in-depth discussion session will follow oral presentations. Oral presentation sessions are complemented by poster sessions that fall within the central theme. Members from underrepresented groups will be actively recruited as speakers and poster presenters. Key speakers will be asked to organize posters into groups of about five - six each, and will lead their discussion among poster presenters and participating meeting attendees. With the help of session chairs, and in collaboration with presenters, the major impacts of oral and poster presentations will be summarized, including the discussions, and published following the meeting.